Google Maps API Key Setup for Reverse Geocoder

Overview

The Reverse Geocoder uses the Google Maps Geocoding API to convert coordinates into addresses. You'll need to provide your own Google Maps API key (a "Bring Your Own Key" or BYOK model). This guide walks you through the entire setup process step-by-step.

Already Have a Key?

If you've set up a Google Maps API key for our Driving Distance Calculator, you can reuse the same key - no need to create a new one! Just paste it into the setup form and you're done.

Why You Need Your Own API Key

Benefits of BYOK:

Lower cost - Google gives you $200/month in free credit (~40,000 free requests/mo)
No per-request fees from us - you only pay Google's direct API costs
Full control - set your own usage limits and billing alerts
Better privacy - your coordinates go directly to Google, not through our proxy

Google's pricing: ~$5 per 1,000 geocoding requests (after free $200/month credit)

Step-by-Step Setup

Step 1: Create a Google Cloud Project

Go to Google Cloud Console

Visit console.cloud.google.com and sign in with your Google account (or create one if needed).

Create a New Project

Click the project dropdown in the top navigation bar, then click New Project. Give it a name like "Custom Web Tools - Maps API" and click Create.

Wait for Project Creation

Google takes 10-30 seconds to create your project. You'll see a notification when it's ready.

First-Time Users

If this is your first Google Cloud project, you'll be prompted to accept the terms of service and may need to verify your account.

Step 2: Enable the Geocoding API

Open the API Library

From the Cloud Console homepage, click APIs & Services > Library in the left sidebar (or use the search bar to find "API Library").

Search for "Geocoding API"

Type "Geocoding API" into the search bar. Click on Geocoding API (not "Geolocation API" or "Maps JavaScript API" - make sure it says "Geocoding").

Click "Enable"

Click the blue Enable button. This activates the Geocoding API for your project.

Screenshot description: You'll see a page titled "Geocoding API" with an "Enable" button at the top. The page shows API details including pricing ($5 per 1,000 requests) and a link to documentation.

Enable the Correct API

Make sure you enable Geocoding API specifically. Google has many Maps-related APIs - enabling the wrong one won't work with our tool.

Step 3: Create an API Key

Go to Credentials

Click APIs & Services > Credentials in the left sidebar.

Create Credentials

Click the blue + Create Credentials button at the top, then select API Key from the dropdown.

Copy Your API Key

A popup appears with your new API key (a long string starting with "AIza..."). Click the Copy button to copy it to your clipboard.

Save Your Key

Paste your API key into a text file or note for safekeeping. You'll need it in Step 5.

Screenshot description: The "API key created" popup shows your key with a copy button and a link to "Restrict Key". The key looks like: AIzaSyC4sZH9tBW3EuT-9xYzK1pQ2rL0mN8oP6U (example).

Free Credit Applied Automatically

Google automatically applies $200/month in free credit to your first billing account. You won't be charged unless you exceed 40,000 geocoding requests per month.

Step 4: Restrict Your API Key (Recommended)

For security, restrict your API key so it can only be used with the Geocoding API:

Click "Restrict Key"

In the API key popup (or from the Credentials page), click Restrict Key or the key name to open settings.

Set Application Restrictions

Under Application restrictions, select HTTP referrers (websites).

Add Allowed Referrers

Click + Add an item and enter:

https://customwebtools.com/
http://localhost/ (for testing, remove after setup)

Set API Restrictions

Under API restrictions, select Restrict key.

Select Geocoding API

From the dropdown, choose Geocoding API. Uncheck any other APIs.

Save Changes

Click the blue Save button at the bottom.

Why Restrict Your Key?

Restricting your key prevents unauthorized use if it's accidentally exposed. Only requests from customwebtools.com (or localhost for testing) will work, and only for the Geocoding API.

Screenshot description: The "Edit API key" page shows two sections: "Application restrictions" with a text field for referrer URLs, and "API restrictions" with a dropdown to select specific APIs.

Step 5: Enable Billing (Required)

Google requires a billing account even though you get $200/month free credit:

Go to Billing

Click Billing in the left sidebar (or search "Billing" in the top search bar).

Link a Billing Account

Click Link a Billing Account or Create Billing Account if you don't have one.

Enter Payment Method

Provide a credit/debit card. Google will charge $1 temporarily to verify the card (refunded immediately).

Confirm Billing

Complete the billing setup. Your $200/month free credit will now be active.

You Won't Be Charged (Probably)

Most users stay well within the $200/month free tier. To process 40,000 coordinates per month (the free limit), you'd need to run ~270 batches of 100 coordinates every single day. Set up billing alerts (next step) for peace of mind.

Step 6: Set Up Billing Alerts (Optional but Recommended)

To avoid surprise charges if you exceed the free tier:

Go to Budgets & Alerts

In the Cloud Console, go to Billing > Budgets & alerts.

Create a Budget

Click + Create Budget.

Set Budget Amount

Enter $200 (your free credit amount) and choose Monthly as the time period.

Configure Alerts

Check Email alerts and set thresholds at 50%, 90%, and 100% of budget.

Save Budget

Click Finish to save. You'll now get email alerts if you approach the free tier limit.

Alert Example

If you set a $200 monthly budget with 50%/90%/100% alerts, you'll get emails when you've used $100 (50%), $180 (90%), and $200 (100%) worth of API calls. This gives you time to adjust usage before incurring charges.

Step 7: Add Your API Key to Custom Web Tools

Now that your Google Cloud setup is complete, add your key to the Reverse Geocoder:

Go to the Tool

Visit Reverse Geocoder and log in to your Custom Web Tools account.

Open Setup Section

Scroll to the Setup section (above the coordinate input form).

Paste Your API Key

Paste your Google Maps API key (the string starting with "AIza...") into the Google Maps API Key field.

Save Configuration

Click the Save Configuration button. Your key is encrypted and stored securely.

Start Converting

You're all set! Scroll up to the main form and start converting coordinates to addresses.

Setup Complete

Your API key is now configured. All reverse geocoding requests will use your key, and usage will appear in your Google Cloud Console billing dashboard.

Cost Calculator

Use this calculator to estimate your monthly Google Maps API costs:

Conversions per Month	Requests to Google	Cost After Free Credit
0 - 40,000	0 - 40,000	$0 (free tier)
50,000	50,000	$50 ($250 total - $200 credit)
100,000	100,000	$300 ($500 total - $200 credit)
200,000	200,000	$800 ($1,000 total - $200 credit)

Formula: (Total requests × $0.005) - $200 free credit = Your cost

Example

If you process 50,000 coordinates per month:

Google charges $0.005 per request = $250 total
Minus $200 free credit = $50/month actual cost
Plus $19.99 CWT subscription = $69.99/month total

Still cheaper than competitors who charge $0.01-0.02 per coordinate with no free tier!

Reusing Your API Key for Other Tools

Your Google Maps API key works with multiple Custom Web Tools:

Tool	Uses Same Key?	Additional APIs Needed?
Reverse Geocoder	Yes	Geocoding API (already enabled)
Driving Distance Calculator	Yes	Distance Matrix API (enable separately)
Future geocoding tools	Yes	Geocoding API (already enabled)

To use your key with the Driving Distance Calculator:

Go to APIs & Services > Library in Google Cloud Console
Search for "Distance Matrix API" and click Enable
Use the same API key - no new key needed!

One Key for All CWT Tools

Create one API key, enable all the APIs you need, and reuse it across every CWT tool. Simpler to manage, and all usage counts toward the same $200/month free credit.

Troubleshooting

"API key not valid" error

Common causes:

Key was copied incorrectly (extra spaces, missing characters)
API key restrictions are too strict (check referrer URLs)
Geocoding API not enabled in Google Cloud Console
Billing not set up (required even with free tier)

Fix: Go back to Google Cloud Console, verify the Geocoding API is enabled, check key restrictions, and ensure billing is linked.

"Quota exceeded" error

You've used more than 40,000 requests this month (exceeded free tier). Options:

Wait until next month for quota to reset
Add more budget in Google Cloud Console to continue using the tool
Check for duplicate coordinate processing (cache results to avoid re-processing)

"This API project is not authorized" error

Your API key restrictions are blocking the request. In Google Cloud Console:

Go to Credentials and click your API key
Under Application restrictions, verify https://customwebtools.com/* is listed
Under API restrictions, verify Geocoding API is selected
Save changes and try again

I can't find my API key

Lost your key? Generate a new one:

Go to APIs & Services > Credentials in Google Cloud Console
Delete the old key (if found) or leave it
Click + Create Credentials > API Key
Copy the new key and update it in Custom Web Tools setup

Don't Share Your API Key

Treat your API key like a password. Never share it publicly or commit it to code repositories. If exposed, regenerate a new key in Google Cloud Console immediately.

Next Steps

Need help with setup? Contact support@customwebtools.com with your Google Cloud project ID (not your API key!) and we'll help troubleshoot.

Last Updated: 2026-02-19 | Setup Time: ~15 minutes for first-time users